1 /* 2 * Access to user system call parameters and results 3 * 4 * Copyright (C) 2008 Red Hat, Inc. All rights reserved. 5 * 6 * This copyrighted material is made available to anyone wishing to use, 7 * modify, copy, or redistribute it subject to the terms and conditions 8 * of the GNU General Public License v.2. 9 * 10 * See asm-generic/syscall.h for descriptions of what we must do here. 11 */ 12 13 #ifndef _ASM_SYSCALL_H 14 #define _ASM_SYSCALL_H 1 15 16 #include <uapi/linux/audit.h> 17 #include <linux/sched.h> 18 #include <linux/thread_info.h> 19 20 /* ftrace syscalls requires exporting the sys_call_table */ 21 #ifdef CONFIG_FTRACE_SYSCALLS 22 extern const unsigned long sys_call_table[]; 23 #endif /* CONFIG_FTRACE_SYSCALLS */ 24 25 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) 26 { 27 /* 28 * Note that we are returning an int here. That means 0xffffffff, ie. 29 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel. 30 * This is important for seccomp so that compat tasks can set r0 = -1 31 * to reject the syscall. 32 */ 33 return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1; 34 } 35 36 static inline void syscall_rollback(struct task_struct *task, 37 struct pt_regs *regs) 38 { 39 regs->gpr[3] = regs->orig_gpr3; 40 } 41 42 static inline long syscall_get_return_value(struct task_struct *task, 43 struct pt_regs *regs) 44 { 45 return regs->gpr[3]; 46 } 47 48 static inline void syscall_set_return_value(struct task_struct *task, 49 struct pt_regs *regs, 50 int error, long val) 51 { 52 /* 53 * In the general case it's not obvious that we must deal with CCR 54 * here, as the syscall exit path will also do that for us. However 55 * there are some places, eg. the signal code, which check ccr to 56 * decide if the value in r3 is actually an error. 57 */ 58 if (error) { 59 regs->ccr |= 0x10000000L; 60 regs->gpr[3] = error; 61 } else { 62 regs->ccr &= ~0x10000000L; 63 regs->gpr[3] = val; 64 } 65 } 66 67 static inline void syscall_get_arguments(struct task_struct *task, 68 struct pt_regs *regs, 69 unsigned int i, unsigned int n, 70 unsigned long *args) 71 { 72 unsigned long val, mask = -1UL; 73 74 BUG_ON(i + n > 6); 75 76 #ifdef CONFIG_COMPAT 77 if (test_tsk_thread_flag(task, TIF_32BIT)) 78 mask = 0xffffffff; 79 #endif 80 while (n--) { 81 if (n == 0 && i == 0) 82 val = regs->orig_gpr3; 83 else 84 val = regs->gpr[3 + i + n]; 85 86 args[n] = val & mask; 87 } 88 } 89 90 static inline void syscall_set_arguments(struct task_struct *task, 91 struct pt_regs *regs, 92 unsigned int i, unsigned int n, 93 const unsigned long *args) 94 { 95 BUG_ON(i + n > 6); 96 memcpy(®s->gpr[3 + i], args, n * sizeof(args[0])); 97 98 /* Also copy the first argument into orig_gpr3 */ 99 if (i == 0 && n > 0) 100 regs->orig_gpr3 = args[0]; 101 } 102 103 static inline int syscall_get_arch(void) 104 { 105 int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64; 106 #ifdef __LITTLE_ENDIAN__ 107 arch |= __AUDIT_ARCH_LE; 108 #endif 109 return arch; 110 } 111 #endif /* _ASM_SYSCALL_H */ 112